A New Parameterization of Coastal Drag to Simulate Landfast Ice in Deep Marginal Seas in the Arctic

Abstract

Landfast ice is defined as "sea ice that stays fast along the coast where it is attached to the shore, to an ice wall, to an ice front, or over shoals, or between grounded icebergs." (World Meteorological Organization, 1970). Landfast ice is a common phenomenon in polar winter. It forms in the autumn as onshore winds thicken and consolidate the ice along the shore until it breaks up in spring. The extent of landfast ice in the Arctic varies with water depth and slope of the continental shelf (Kwok, 2018;Yu et al., 2014). Anchored pressure ridges ground coastal sea ice in shallow water all along the coast of Alaska and the Laptev Sea. Landfast ice can also be formed in deep marginal regions by lateral propagation of internal stresses from contact points with the coastline, as seen in the Kara Sea (Li et al., 2020). Furthermore, landfast ice can also be landlocked ice that is confined in the narrow channels of the Canadian Arctic Archipelago (Howell et al., 2016;Melling, 2002). In Antarctica, where the bathymetric features are very different from the Arctic, landfast ice can be found in 400-500 m deep water, pinned by grounded icebergs (Fraser et al., 2012(Fraser et al., , 2020Massom et al., 2001).Landfast ice is an important player in Arctic and Antarctic coastal environments. It forms a stable cover that decreases the transfer of heat, moisture, and momentum between the atmosphere and the ocean (Johnson et al., 2012;Lemieux et al., 2016). As a consequence, ocean mixing is generally reduced underneath a landfast

Using Icepack to reproduce Ice Mass Balance buoy observations in landfast ice: improvements from the mushy layer thermodynamics

“…In many areas, for instance, the landfast ice is held by the grounding of ice keels on the ocean floor, which involves prior ridging (dynamics) of sufficiently thick ice (thermodynamics). In absence of ice grounding, landfast ice can form during periods of calm and cold weather (Divine et al, 2004;Kirillov et al, 2021) during which leads freeze to a sufficient ice thickness for the unconsolidated ice floes to coalesce together (thermodynamics), allowing the formation of ice arches between pining points that resist subsequent surface forcings (dynamics, Dammann et al, 2019;Liu et al, 2022). In sea ice models, this inter-play between thermodynamic and dynamic factors is represented by ice thickness dependencies in the dynamical parameters, such as the seabed stress term (Lemieux et al, 2015) or the material strength parameters (Dumont et al, 2009;Lemieux et al, 2016;Plante et al, 2020).…”